Performance evaluation of composite prestressed concrete slab bridges

The results from a research project that evaluated the long-term performance of bridges constructed with composite prestressed concrete panels are summarized. The particular construction system investigated used full-span prestressed concrete panels that would be typical for bridges with spans of 12 m (40 ft) or less. A full-scale bridge specimen was constructed and subjected to 5 million cycles of service loading and 48 weeks of durabillity exposure cycling. This was done to assess the potential for delamination as well as the resistance to chloride-induced reinforcement corrosion. The exposure cycling greatly accelerated the rate of penetration of chlorides, producing concentrations in the deck that exceeded those from bridges that had been in service for nearly 40 years. The results from this study showed that long-term composite behavior can he achieved in these structures by applying a raked finish to the top surface of the pre-stressed panels. Corrosion measurements revealed the need to modify the positive-moment connections at interior piers to provide a more durable structure.